feat: persist settings and enrich conversation context

tests/chat-service-username-persist.test.ts

@@ -70,6 +70,73 @@ describe('ChatService username persistence', () => {
     expect(svc.resolveSenderDisplay('@t2_unknown:reddit.com')).toBe('t2_unknown');
   });
 
+  it('starts a conversation with the t2 ID supplied by the Reddit listing', async () => {
+    const logger = createMockLogger();
+    const matrix = buildMatrix();
+    matrix.sendInitialDirectMessage = vi.fn().mockResolvedValue({
+      roomId: '!room:reddit.com',
+      eventId: '$event',
+    });
+    const usernameResolver = {
+      resolveT2Ids: vi.fn().mockResolvedValue({}),
+      resolveUsernameToT2: vi.fn().mockRejectedValue(new Error('profile lookup returned 403')),
+    };
+    const svc = new ChatService(
+      matrix,
+      logger,
+      undefined, undefined, undefined, usernameResolver,
+      tmpCache(logger),
+      undefined,
+      undefined,
+      authenticatedAccountAuth,
+    );
+
+    const chat = await svc.startConversation('alice', 'hello', 't2_abc123');
+
+    expect(chat?.username).toBe('alice');
+    expect(usernameResolver.resolveUsernameToT2).not.toHaveBeenCalled();
+    expect(matrix.sendInitialDirectMessage).toHaveBeenCalledWith(
+      '@t2_abc123:reddit.com',
+      'hello',
+    );
+  });
+
+  it('uses the durable username mapping before a live profile lookup', async () => {
+    const db = new Database(':memory:');
+    runMigrations(db);
+    const repo = new RedditUsersRepository(db);
+    repo.upsert({ t2Id: 't2_cached', username: 'alice' });
+    const logger = createMockLogger();
+    const matrix = buildMatrix();
+    matrix.sendInitialDirectMessage = vi.fn().mockResolvedValue({
+      roomId: '!room:reddit.com',
+      eventId: '$event',
+    });
+    const usernameResolver = {
+      resolveT2Ids: vi.fn().mockResolvedValue({}),
+      resolveUsernameToT2: vi.fn().mockRejectedValue(new Error('profile lookup returned 403')),
+    };
+    const svc = new ChatService(
+      matrix,
+      logger,
+      undefined, undefined, undefined, usernameResolver,
+      tmpCache(logger),
+      undefined,
+      repo,
+      authenticatedAccountAuth,
+    );
+
+    const chat = await svc.startConversation('ALICE', 'hello');
+
+    expect(chat?.username).toBe('ALICE');
+    expect(usernameResolver.resolveUsernameToT2).not.toHaveBeenCalled();
+    expect(matrix.sendInitialDirectMessage).toHaveBeenCalledWith(
+      '@t2_cached:reddit.com',
+      'hello',
+    );
+    db.close();
+  });
+
   it('upgrades cached chats with t2_ usernames from the db map on loadCache', async () => {
     const db = new Database(':memory:');
     runMigrations(db);